Downlink multiplexing

ABSTRACT

A communications node includes a memory configured to store allocation data defining an allocation of persistent downlink resources for use in communicating data between the communications node and another node of a communications system within predetermined transmission time intervals (TTIs), a receiver configured to receive control data relating to a dynamic allocation of resources to be used in a current TTI, and a controller configured to determine if a C-RNTI is present in the control data for a TTI for which a User Equipment (UE) includes persistent downlink resources, determine that the resource allocation indicated on a control channel for the TTI overrides the persistent downlink resources for the TTI, when a C-RNTI is present in the control channel for a TTI for which the UE has persistent downlink resources, and allocate persistent downlink resources for a Hybrid Automatic Repeat Request (HARQ) transmission.

The present application is a Continuation Application of U.S. patentapplication Ser. No. 13/731,369, filed on Dec. 31, 2012, which is aContinuation Application of U.S. patent application Ser. No. 12/733,129,filed on Feb. 12, 2010, now U.S. Pat. No. 8,594,040, which is based onand claims priority from international application No.PCT/JP2008/064675, filed on Aug. 12, 2008, which is based on and claimspriority from GB0715822.3, filed on Aug. 14, 2007, the entire contentsof which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to the communication of data within amobile (cellular) communication system. The invention has particular,although not exclusive relevance to the allocation of sub-carriers usedin a wireless communication system.

BACKGROUND ART

OFDMA and single carrier FDMA have been selected as the downlink anduplink multiple access schemes for the E-UTRA (Evolved UniversalTerrestrial Radio Access) air interface currently being studied in 3GPP(which is a standard based collaboration looking at the future evolutionof third generation mobile telecommunication systems). Under the E-UTRAsystem, a base station which communicates with a number of user devicesallocates the total amount of time/frequency resource (depending onbandwidth) among as many simultaneous users as possible, in order toenable efficient and fast link adaptation and to attain maximummulti-user diversity gain.

The E-UTRA system provides for both real time (RT) services, such asVoIP (Voice over Internet Protocol), and non-real time (NRT) services,such as web browsing. The time/frequency resources that allow userdevices to use these services may be allocated dynamically (i.e., ondemand at the time that they are needed) or persistently depending onthe service used. For example, for real time services such as VoIP,where the amount of resources needed is known in advance, the userdevices can be allocated the resources in advance (persistentlyallocated), for example at the time of the call setup. For more “bursty”traffic, such as web browsing traffic, the resources would be allocateddynamically based on the amount of data to be transmitted between theuser device and the network at the time.

The current working assumption in RAN1 is that if the user device haspersistently allocated resources in a given Transmission Time Interval(TTI); no other resources could be allocated to the user device fordata/signalling within the same TTI, except within the DynamicBroadcasting Channel (DBCH).

DISCLOSURE OF INVENTION

According to one exemplary aspect, the present invention provides asystem in which user devices can use both dynamically and persistentlyallocated resources within the same TTI, to receive downlink data fromthe network.

One exemplary embodiment provides a method performed by a node of acommunications system, the method comprising: storing allocation datadefining persistently allocated resources for use in communicating databetween the node and another node of the communications system withinpredetermined transmission time intervals; receiving control datadefining an allocation of new resources to be used; determining if thereceived control data includes a predefined bit pattern; and dependingon whether or not said determining step determines that said receivedcontrol data includes said predefined bit pattern: i) communicating withsaid other node using the new resources instead of the persistentlyallocated resources identified by the stored allocation data; or ii)communicating with said other node using the resources identified by thestored allocation data and the new resources allocated by the receivedcontrol data.

Preferably, the control data has a predefined structure including an IDfield for holding ID data identifying the node, an allocation field forholding data defining the new resources and one or more other fields forholding parameters required for communicating with the new resources,wherein when the control data is for defining a reallocation of saidpersistently allocated resources, at least one of said one or more otherfields includes said predefined bit pattern instead of one or more ofsaid parameters and wherein the node uses previous parameters for theone or more parameters replaced by said predefined bit pattern.

In one exemplary embodiment, the control data includes an ID field forID data identifying the node, an allocation data field for allocationdata defining the new resources and an antenna data field and whereinsaid predefined bit pattern is defined by data within said antenna datafield.

In another exemplary embodiment, the control data includes an ID fieldfor ID data identifying the node, an allocation data field forallocation data defining the new resources and a transport format datafield and wherein said predefined bit pattern is defined by data withinsaid transport format data field.

In a further exemplary embodiment, the control data includes an ID fieldfor ID data identifying the node, an allocation data field forallocation data defining the new resources and an HARQ (Hybrid AutomaticRepeat Request) data field and wherein said predefined bit pattern isdefined by data within said HARQ data field.

In one exemplary embodiment the control data includes predefined datafields for: ID data, resource assignment data, antenna data, transportformat data and HARQ data, and wherein said predefined bit pattern islocated within one or more of the antenna data field, the transportformat data field and the HARQ data field. Preferably the predefined bitpattern is defined by a reserved value not used to define thecorresponding parameter value.

In some exemplary embodiments, the transport format data field willinclude a subfield for a modulation scheme to use and a subfield fordefining a payload size of data packets to be communicated using theassigned resources and wherein the predefined bit pattern is locatedwithin one of those subfields.

The resource allocations are preferably for allocating downlinkresources, although in other exemplary embodiments, they may be used todefine uplink resources. When the resource allocations relate todownlink allocations, the node may also transmit multiple ACK/NACKs. Inthis case, a multi-bit modulation scheme is preferably used, such asQPSK (Quadrature Phase-Shift Keying) instead of the usual binarymodulation scheme such as BPSK (Binary Phase-Shift Keying). In this way,the up link control channel used for ACK/NACKs also does not need tochange.

An exemplary embodiment also provides a method performed by a node of acommunications system, the method comprising: storing allocation datadefining persistently allocated resources for use in communicating databetween the node and another node of the communications system withinpredetermined transmission time intervals; generating control datadefining an allocation of new resources to be used; determining whetheror not to include a predefined bit pattern within the control data,depending on whether or not the new resources are to be used in additionto the persistently allocated resources or instead of the persistentlyallocated resources; transmitting the generated control data to theother node for controlling the resources used; and depending on whetheror not said control data includes said predefined bit pattern: i)communicating with said other node using the new resources instead ofthe persistently allocated resources identified by the stored allocationdata; or ii) communicating with said other node using the persistentlyallocated resources identified by the stored allocation data and the newresources allocated by the received control data.

Preferably, the generating step generates control data having apredefined structure including an ID field for holding ID dataidentifying the node, an allocation field for holding data defining thenew resources and one or more other fields for holding parametersrequired for communicating with the new resources, wherein when saiddetermining step determines that the new resources are to be usedinstead of said persistently allocated resources, said generating stepsets one or more of said other fields with said predefined bit patterninstead of the corresponding one or more parameters and wherein whencommunicating with the other node using the new resources, the node usesthe corresponding one or more parameters forming part of said storedallocation data for the one or more parameters replaced by saidpredefined bit pattern.

The invention provides, for all methods disclosed, correspondingcomputer programs or computer program products (computer implementableinstructions product) for execution on corresponding equipment, theequipment itself (user equipment, nodes or components thereof) andmethods of updating the equipment.

These and various other aspects of the invention will become apparent,from the following detailed description of exemplary embodiments whichare given by way of example only and which are described with referenceto the accompanying Figures in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a communication system comprising anumber of user mobile (cellular) telephones which communicate with abase station connected to the telephone network;

FIG. 2 is a schematic diagram illustrating the structure of theTransmission Time Intervals used in the communication system shown inFIG. 1;

FIG. 3 is a block diagram illustrating the main components of the basestation shown in FIG. 1; and

FIG. 4 is a block diagram illustrating the main components of one of themobile telephones shown in FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Overview

FIG. 1 schematically illustrates a mobile (cellular) telecommunicationsystem 1 in which users of mobile telephones 3-0, 3-1, and 3-2 cancommunicate with other users (not shown) via a base station 5 and atelephone network 7. In this exemplary embodiment, the base station 5uses an orthogonal frequency division multiple access (OFDMA) techniquein which the data to be transmitted to the mobile telephones 3 ismodulated onto a plurality of sub-carriers. Different sub-carriers areallocated to each mobile telephone 3 depending on the amount of data tobe sent to the mobile telephone 3. In this exemplary embodiment the basestation 5 also allocates the sub-carriers used to carry the data to therespective mobile telephones 3 in order to try to maintain a uniformdistribution of the mobile telephones 3 operating across the basestation's bandwidth. To achieve these goals, the base station 5dynamically allocates sub-carriers for each mobile telephone 3 andsignals the allocations for each time point (sub-frame) to each of thescheduled mobile telephones 3.

In this exemplary embodiment, the base station 5 may dynamicallyallocate resources for downlink transmissions during transmissionintervals in which the mobile telephone 3 is already scheduled toreceive persistently scheduled data. In order to ensure that the mobiletelephone 3 interprets the dynamic allocation of resources correctly,the base station 5 encodes appropriate data into the control channelused to carry the data defining the new allocation. It does this, inthis exemplary embodiment, without changing the DL L1/L2 control channelstructure used to signal the resource allocations.

Time/Frequency Resources

In this exemplary embodiment, the available transmission bandwidth isdivided into a number of resource blocks, each of which comprises anumber of contiguous sub-carriers (i.e. 12 subcarriers) arranged incontiguous blocks. Different mobile telephones 3 are allocated differentresource block(s) (sub-carriers) for transmitting/receiving their data.FIG. 2 illustrates E-UTRA's latest definition of the transmissionchannel as comprising a sequence of 1 ms Transmission Time Intervals(TTIs) 11-1, 11-2, each of which consists of two 0.5 ms slots 13-1 and13-2. As shown, the available transmission bandwidth is divided into Sresource blocks (RBs) 15-1 to 15-s and each mobile telephone 3 isscheduled to transmit its uplink data and receive its downlink data inselected slots 13 and in selected resource block (RB) 15. It is alsopossible each mobile telephone 3 to be assigned multiple resource blocks(RBs).

Base Station

FIG. 3 is a block diagram illustrating the main components of the basestation 5 used in this exemplary embodiment. As shown, the base station5 includes a transceiver circuit 21 which is operable to transmitsignals to and to receive signals from the mobile telephones 3 via oneor more antennae 23 (using the above described sub-carriers) and whichis operable to transmit signals to and to receive signals from thetelephone network 7 via a network interface 25. The operation of thetransceiver circuit 21 is controlled by a controller 27 in accordancewith software stored in memory 29. The software includes, among otherthings, an operating system 31 and a resource allocation module 33. Theresource allocation module 33 is operable for allocating thesub-carriers used by the transceiver circuit 21 in its communicationswith the mobile telephones 3. As shown in FIG. 3, the resourceallocation module 33 includes control parameter generator module 35 forgenerating the required control parameters for defining the allocatedresources.

Mobile Telephone

FIG. 4 schematically illustrates the main components of each of themobile telephones 3 shown in FIG. 1. As shown, the mobile telephones 3include a transceiver circuit 71 which is operable to transmit signalsto and to receive signals from the base station 5 via one or moreantennae 73. As shown, the mobile telephone 3 also includes a controller75 which controls the operation of the mobile telephone 3 and which isconnected to the transceiver circuit 71 and to a loudspeaker 77, amicrophone 79, a display 81, and a keypad 83. The controller 75 operatesin accordance with software instructions stored within memory 85. Asshown, these software instructions include, among other things, anoperating system 87 and a communications module 89. In this exemplaryembodiment, the communications module 89 includes a control parameterinterpreter module 91 for interpreting received control parameters thatdefine a resource allocation.

In the above description, the base station 5 and the mobile telephones 3are described for ease of understanding as having a number of discretemodules (such as the resource allocation module, control parametergenerator module, communications module and control parameterinterpreter module). Whilst these modules may be provided in this wayfor certain applications, for example where an existing system has beenmodified to implement the invention, in other applications, for examplein systems designed with the inventive features in mind from the outset,these modules may be built into the overall operating system or code andso these modules may not be discernible as discrete entities.

Operation

The current E-UTRAN (Evolved Universal Terrestrial Radio Access Network)specification states that in the downlink, resources (physical resourceblocks (PRBs) and Modulation & coding scheme (MCS)) can be dynamicallyallocated to a mobile telephone 3 at each TTI via the C-RNTI on theL1/L2 control channel(s). A mobile telephone 3 always monitors the L1/L2control channel(s) in order to find a possible allocation when itsdownlink reception is enabled (activity governed by DRX—discontinuousreception).

In addition, E-UTRAN can allocate predefined downlink resources for thefirst HARQ transmissions to mobile telephones 3. When required,retransmissions are explicitly signalled via the L1/L2 controlchannel(s). In the sub-frames where the mobile telephone 3 has beenpre-assigned resources, if the mobile telephone 3 cannot find its C-RNTIon the L1/L2 control channel(s), a downlink transmission according toany pre-defined allocation that the mobile telephone 3 has been assignedin the TTI is assumed. As a result, the mobile telephone 3 performsblind decoding of the pre-defined resources (the subset of pre-definedresources shall be set in accordance with the mobile telephone'scapability). Otherwise, in the sub-frames where the mobile telephone 3has been pre-assigned resources, if the mobile telephone 3 finds itsC-RNTI on the L1/L2 control channel(s), the L1/L2 control channelallocation overrides the pre-defined allocation for that TTI and themobile telephone 3 does not perform blind decoding of the pre-definedresources.

Given this current proposal, if the base station 5 needs to dynamicallyallocate downlink resources in the same TTI where predefined downlinkresources (persistently scheduled) for the first HARQ transmissions arescheduled for the mobile telephone 3, a mechanism has to be providedwhich will enable the mobile telephone 3 to interpret the DL resourceallocation differently without changing the DL control channelstructure.

There are four possible allocations that can happen as shown in Table 1.Persistently scheduled allocations are not signalled in the DL L1/L2control channel; as they are signalled from higher layers (i.e. L3).

TABLE 1 Four Possible Allocations that can happen Reallocation ofPersistently Allocated New dynamic Resources allocated resourcesComments Persistently scheduled Not-allocated. There are no controlresources go as usual, channels there is no control channel.Reallocation overrides the Not-allocated. There is one controlpersistently scheduled channel resources, there is control channel.Persistently scheduled Allocated, there is There is one controlresources go as usual, control channel. channel there is no controlchannel. Reallocation overrides the Allocated, there is There are twocontrol persistently scheduled control channel. channels resources,there is control channel.

As can be seen from Table 1, whenever a dynamic allocation is being madeor whenever the persistently scheduled resources are to be reallocated,the base station 5 must generate and transmit control data over acontrol channel to the mobile telephone 3 to define the desired change.The last row of the table defines the situation where the base station 5wishes to provide a dynamic allocation of the resources to be used inthe current TTI and at the same time change the persistently allocatedresources. This will require the use of two control channels within thesame TTI to carry the appropriate control data to the mobile telephone3. Currently, the proposal is to have a maximum of one control channelwithin each TTI for each mobile telephone 3. Therefore, the situationdefined in the last row of Table 1 would not be supported by the currentproposal. However, if the current proposal changes to allow thetransmission of two control channels for a single mobile telephone 3 inthe same TTI, then this situation would also be supported.

As will be apparent from the above discussion, the two cases that needto be distinguished by the mobile telephone 3 within the same TTI are:

-   -   1) Reallocation of predefined (persistently scheduled) downlink        resources; and    -   2) New dynamic allocated resources.

The DL Control Channel Parameters that are generated by the base station5 and transmitted to the mobile telephone 3 are shown in Table 2 below.The inventors believe that the required distinction can be achieved ifthe base station 5 sets the Transport Format or HARQ related informationdifferently for the two cases and the mobile telephone 3 interprets thecontrol data accordingly.

TABLE 2 DL Control Channel Parameters Control signaling informationNumber of bits Comments Mobile telephone 16 16-24 bit CRC ID ResourceMaximum 18, 28, Location of the resource blocks assignment 37 bits for5, assigned to each mobile telephone 10, 20 MHz in a TTI for DLtransmission. Multi-antenna [2] Antenna information info Transport [8] 2bits for modulation scheme, 6 Format Info. bits for payload size.(Transport Block Size + MCS) HARQ-related [5] 3 bits for process number,2 bits information for redundancy version and new data indicator.

As shown in table 2, the DL Control Channel parameters that need to beset for the two cases are:

-   -   Reallocation of Persistently Allocated Resources: Multi-antenna        info/Transport Format/HARQ related Information can be set to        specific pattern. Because, some of the information carried on        the Multi-antenna info, Transport Format and HARQ related        Information are not changed during reallocation of the        persistently allocated resources, the pattern can be the two        bits of the Multi-antenna info (for example bit pattern 11),        and/or the last two bits of the Modulation scheme (for example        bit pattern 11) in the Transport Format and/or the last three        bits of the HARQ process number (for example bit pattern 111).        Which part of the control parameters would be set in this        pattern is, in this exemplary embodiment, determined in advance        and known to the mobile telephone 3 and the base station 5.    -   New Resource allocation for Data/Signalling: All the control        channel parameters would be set as usual for dynamically        scheduled packet data.

Therefore, if the mobile telephone 3 receives DL control channelparameters in a current TTI in which it has persistently allocatedresources, it first checks to see if the received parameters contain thepredefined bit pattern in the appropriate location. If it finds thepattern, then it interprets the allocation as a reallocation of thepersistently allocated resources; and if it does not find the pattern,then it treats the allocation as a new allocation for dynamicallyscheduled packet data. If it is a reallocation of the persistentlyallocated resources, the missing parameter information replaced by thebit pattern is taken from the control data that originally signalled thepersistent allocation. For example if the bit pattern is included in themulti-antenna information field of the control data, then the mobiletelephone 3 assumes that this information is not changed and uses themulti-antenna information that is stored for the persistently allocatedresources (and which was signalled to the mobile telephone 3 at the timethat the persistent allocation was originally signalled).

ACK/NACK Feedback

The proposed DL multiplexing deals only with a mixture of persistentlyscheduled and dynamically scheduled services. In this case, two HARQprocesses are possible at maximum, resulting in two ACK/NACKs (2 bits)to be sent on the UL feedback (as opposed to one bit currently). Thisdata can be sent using QPSK modulation and so, with this proposal, nomodification is required for the UL control signalling either.

Conclusion

This patent application describes DL multiplexing for the case ofsimultaneous transmission of persistently scheduled and dynamicallyscheduled services. The advantages of doing so include:

1) From a scheduling point of view, having both Persistent and Dynamicallocation within one sub frame would be very efficient.

2) Resources for RRC/L2 signalling/Data could be dynamically allocatedin the same sub frame in which VoIP packets are persistently scheduled.

3) Increases DL capacity.

4) Increased Battery life of the mobile telephone 3 as the “On-Duration”of the mobile telephone during DRX operation can be reduced.

5) Different HARQ profile for VoIP (having persistently allocatedresource) and Data (having dynamically allocated resource) is possibleby having separate ACK/NACK for the different bearer types.

In addition, no modification is required to the current DL or UL L1/L2control structure to accommodate the proposed multiplexing. The onlyrequirement is the provision of a mechanism that will allow the mobiletelephone 3 to distinguish between reallocation of PersistentlyAllocated Resources and the allocation of New Dynamic resources, such asby putting a predefined bit pattern in one or more of the DL ControlChannel Parameters for the reallocation of the persistently allocatedresources.

Modifications and Alternatives

A number of detailed exemplary embodiments have been described above. Asthose skilled in the art will appreciate, a number of modifications andalternatives can be made to the above exemplary embodiments whilst stillbenefiting from the inventions embodied therein. By way of illustrationonly a number of these alternatives and modifications will now bedescribed.

In the above exemplary embodiments, a mobile telephone basedtelecommunication system was described in which the above describedsignalling techniques were employed. As those skilled in the art willappreciate, the signalling of such resource allocation data can beemployed in any communication system that uses a plurality ofsub-carriers. In particular, the signalling techniques described abovecan be used in wire or wireless based communications either usingelectromagnetic signals or acoustic signals to carry the data. In thegeneral case, the base station would be replaced by a communication nodewhich communicates with a number of different user devices. User devicesmay include, for example, personal digital assistants, laptop computers,web browsers, etc.

In the above exemplary embodiments, a number of software modules weredescribed. As those skilled will appreciate, the software modules may beprovided in compiled or un-compiled form and may be supplied to the basestation or to the mobile telephone as a signal over a computer network,or on a recording medium. Further, the functionality performed by partor all of this software may be performed using one or more dedicatedhardware circuits. However, the use of software modules is preferred asit facilitates the updating of base station 5 and the mobile telephones3 in order to update their functionalities.

The following is a detailed description of the way in which the presentinventions may be implemented in the currently proposed 3GPP LTEstandard. Whilst various features are described as being essential ornecessary, this may only be the case for the proposed 3GPP LTE standard,for example due to other requirements imposed by the standard. Thesestatements not, therefore, be construed as limiting the presentinvention in any way.

Introduction

The current assumption in RAN 1 is that if the UE is having persistentlyallocated resources in a given TTI for example VoIP Service; no otherresources could be allocated to the UE for data/signalling within thesame TTI except with Dynamic Broadcasting Channel (DBCH). Therestriction of having one transport block per TTI for the unicasttransmissions comes from the fact that there will be only 1 HARQ processfor non-MIMO case.

This issue was last discussed in RAN1#46bis in Seoul, October 06 andsince then there have not been any further discussion on this topic insubsequent meetings. In this contribution, we revisit this workingassumption and discuss if the working assumption needs to be modifiedfor simultaneous reception of persistently scheduled and dynamicallyscheduled services for one user in a TTI for DL transmissions.

Discussion

The main reason for agreeing this working assumption was that the DLcontrol Channel structure and the resources needed for sending HARQACK/NACKS were not clear at that time. However, with progress on the DLControl channel structure: a) the proposal to separate out the ACK/NACKfor persistently scheduled UE's and the dynamically scheduled UE's, b)the L1 L2 signaling is basically not used to assign resources to thepersistently scheduled UEs, we believe that these restrictions are nolonger necessary. Further more, if multiple HARQ processes within onesub frame are allowed, UE could receive both a persistently scheduled(e.g. VOIP) packet and a dynamically scheduled (data) packet in the samesub-frame in the DL transmissions.

The possible benefits this could bring are:

-   -   From scheduling point of view, having both Persistent and        Dynamic allocation within one sub frame would be very efficient.    -   Resources for RRC/L2 signalling/Data could be dynamically        allocated in the same sub frame in which VoIP packets are        persistently scheduled.    -   Increases DL capacity    -   Increased Battery life of the UE as the “On-Duration” of UE        during DRX operation can be reduced.    -   Different HARQ profile for VoIP (having persistently allocated        resource) and Data (having dynamically allocated resource) is        possible by having separate ACK/NACK for different bearer type.

One could argue that this would increase UE complexity; however webelieve that such functionality can be considered as a part of higherclass/category UE. Early deployment UE may not implement suchfunctionality. Mechanism for differentiating new dynamic allocation andpersistent reallocation Stage 2 Technical Specification states that:

“In the downlink, E-UTRAN can dynamically allocate resources (PRBs andMCS) to UEs at each TTI via the C-RNTI on L1/L2 control channel(s). A UEalways monitors the L1/L2 control channel(s) in order to find possibleallocation when its downlink reception is enabled (activity governed byDRX).

In addition, E-UTRAN can allocate predefined downlink resources for thefirst HARQ transmissions to UEs. When required, retransmissions areexplicitly signalled via the L1/L2 control channel(s). In the sub-frameswhere the UE has been pre-assigned resources, if the UE cannot find itsC-RNTI on the L1/L2 control channel(s), a downlink transmissionaccording to any pre-defined allocation that the UE has been assigned inthe TTI is assumed. As a result, the UE performs blind decoding of thepre-defined resources (the subset of pre-defined resources shall be setin accordance to UE's capability). Otherwise, in the sub-frames wherethe UE has been pre-assigned resources, if the UE finds its C-RNTI onthe L1/L2 control channel(s), the L1/L2 control channel allocationoverrides the pre-defined allocation for that TTI and the UE does notperform blind decoding of the pre-defined resources”.

Given this, if we need to dynamically allocate downlink resources in thesame TTI where the predefined downlink resources (persistentlyscheduled) for the first HARQ transmissions are scheduled for a UEs, weneed to define a mechanism which will enable the UE to interpret DLgrant differently without changing the DL control channel structure.

The two cases that need to be distinguished by the UE within the sameTTI are:

-   -   1) Reallocation of predefined (persistently scheduled) downlink        resources    -   2) New dynamic allocated resources.

There are four possible allocations that can happen as shown on Table 1.Persistently scheduled allocation does not use DL L1 L2 control channel,but it is being signalled from higher layers (i.e., L3).

TABLE 1 Four Possible Allocations that can happen Reallocation ofPersistently Allocated New dynamic Resources allocated resourcesComments Persistently scheduled Not-allocated. There are no controlresources go as usual, channels there is no control channel.Reallocation overrides the Not-allocated. There is one controlpersistently scheduled channel resources, there is control channel.Persistently scheduled Allocated, there is There is one controlresources go as usual, control channel. channel there is no controlchannel. Reallocation overrides the Allocated, there is There are twocontrol persistently scheduled control channel. channels resources,there is control channel.

DL Control Channel Parameters are shown in Table 2 below. We believethat the distinction can be done if eNB sets the Transport Format andHARQ related information differently for the two cases and the UEinterprets it accordingly.

As shown on table, DL Control Channel parameters that need to be set byfor two cases are:

-   -   Reallocation of Persistently Allocated Resources: Multi-antenna        info/Transport Format/HARQ related Information can be set to        specific pattern. Because, some of the information carried on        the Multi-antenna info, Transport Format and HARQ related        Information are not changed during reallocation of the        persistently allocated resources. The pattern can be the last        three bits of the Multi-antenna info (11), and or the last two        bits of the Modulation scheme (11) in the Transport Format and        or the last three bits of the HARQ process number (111).    -   New Resource allocation of Data/Signalling: All the parameters        would be set as usual for dynamically scheduled packet data.

TABLE 2 DL Control Channel Parameters Control signaling informationNumber of bits Comments UE ID 16 16-24 bit CRC Resource Maximum 18, 28,Location of the resource blocks assignment 37 bits for 5, assigned toeach UE in a TTI for 10, 20 MHz DL transmission. Multi-antenna [2]Antenna information info Transport [8] 2 bits for modulation scheme, 6Format Info. bits for payload size. (Transport Block Size + MCS)HARQ-related [5] 3 bits for process number, 2 bits information forredundancy version and new data indicator.ACK/NACK Feedback

The proposed DL multiplexing deals only a mixture of persistentlyscheduled and dynamic scheduled services. In this case, two HARQprocesses are possible at maximum, resulting 2 ACK/NACKs (2 bits) to besent on the UL feedback using QPSK modulation. So, with this proposal,no modification is required for the UL control signalling.

CONCLUSION

In this contribution, we have discussed and revisited the DLmultiplexing for the case of simultaneous transmission of persistentlyscheduled and dynamic scheduled services. We highlighted the benefits ofhaving such multiplexing for LTE downlink transmissions. In addition, nomodification is required to the current DL/UL L1 L2 control structure toaccommodate the proposed multiplexing. It is only required todistinguish between reallocation of Persistently Allocated Resources andthe allocation of New Dynamic resources by putting a unique pattern insome of the DL Control Channel Parameters for the reallocation of thePersistently Resources. So, we recommend RAN1/RAN2 to revisit thecurrent working assumption and allow simultaneous reception ofpersistently scheduled and dynamically scheduled services for one userin a TTI for DL transmissions.

This application is based upon and claims the benefit of priority fromUnited Kingdom Patent Application No. 0715822.3, filed on Aug. 14, 2007,the disclosure of which is incorporated herein in its entirety byreference.

The invention claimed is:
 1. A communications node, comprising: a memoryconfigured to store allocation data defining an allocation of persistentdownlink resources for use in communicating data between thecommunications node and another node of a communications system withinpredetermined transmission time intervals (TTIs); a receiver configuredto receive control data relating to a dynamic allocation of resources tobe used in a current TTI; and a controller configured to: determine if aC-RNTI is present in the control data for a TTI for which a UserEquipment (UE) includes persistent downlink resources; determine thatthe resource allocation indicated on a control channel for the TTIoverrides the persistent downlink resources for the TTI, when a C-RNTIis present in the control channel for a TTI for which said UE haspersistent downlink resources; and allocate persistent downlinkresources for a Hybrid Automatic Repeat Request (HARQ) transmission. 2.A communications method, comprising: storing allocation data defining anallocation of persistent downlink resources for use in communicatingdata between a communications node and another node of a communicationssystem within predetermined transmission time intervals (TTIs);receiving control data relating to a dynamic allocation of resources tobe used in a current TTI; determining if a C-RNTI is present in thecontrol data for a TTI for which a User Equipment (UE) includespersistent downlink resources; determining that the resource allocationindicated on the control channel for the TTI overrides the persistentdownlink resources for the TTI, when a C-RNTI is present in the controlchannel for a TTI for which said UE has persistent downlink resources;and allocating persistent downlink resources for a Hybrid AutomaticRepeat Request (HARQ) transmission.
 3. A non-transitorycomputer-readable storage medium encoded with a computer program forcausing a programmable computer device to carry out the method of claim2.